In a turbomachine, such as a gas turbine engine, air is pressurized in a compressor section then mixed with fuel and burned in a combustion section to generate hot combustion gases. The hot combustion gases are expanded within a turbine section of the engine where energy is extracted from the combustion gases to power the compressor section and to produce useful work, such as turning a generator to produce electricity.
The hot combustion gases created in the combustion section travel through a series of turbine stages within the turbine section. A turbine stage may include a row of stationary airfoil assemblies, i.e., vanes, followed by a row of rotating airfoil assemblies, i.e., turbine blades, where the turbine blades extract energy from the hot combustion gases for powering the compressor section and providing output power.
One type of airfoil assembly, i.e., a turbine blade, comprises an airfoil extending from a radially inner platform at a root end to a radially outer portion of the airfoil, and includes opposite pressure and suction sidewalls meeting at leading and trailing edges of the airfoil. After periods of use, it has been found that areas adjacent to locations where the airfoil intersects with the platform become damaged, i.e., cracked, due to overheating and oxidation, such that repair/replacement procedures are required.